Climate change

Balancing greater Sydney's water supply and demand over the long term requires improved understanding of climate cycles and trends, as well as the potential impacts of climate change.

Climate variability relates to the naturally occurring weather events and patterns that have been tracked over time. Historical records show that Sydney’s climate is highly variable, even without climate change impacts. While it is probable there will be severe drought conditions in the future, the exact nature of these droughts—timing, duration and severity—cannot be known. However, we do have a sound understanding of the effects of drought, and the importance of non-rain dependent supplies such as desalination. The 2010 Metropolitan Water Plan contains a range of measures that can be called on when a prolonged drought hits.

To better understand the impacts of climate change on greater Sydney’s water supply system and future urban water demand, a collaborative study titled ‘Climate change and its impacts on water supply and demand in Sydney’ (known as the Sydney Water Balance Project) was undertaken. The collaboration involved the NSW Office of Water, the Commonwealth Department of Climate Change and Energy Efficiency, the former NSW Department of Environment Climate Change and Water, Sydney Water, Sydney Catchment Authority, the University of New South Wales and the CSIRO. The final report was released in November 2010.

The results of the Sydney Water Balance Project provide information on how greater Sydney’s water supply may be affected by climate change over time. However, climate change modelling is an evolving science and current projections contain considerable uncertainty. This is due to uncertainties about the future levels of greenhouse gas emissions, the lack of consistent climate data and limitations of global climate models to estimate climate impacts at the regional level and to model future droughts..

Given that information about climate change projections and anticipated impacts will improve over time, it is important to maintain our flexible approach to managing greater Sydney’s water supply.